The spinal column in man comprises 7 cervical, 12 dorsal, 5 lumbar, 5 sacral, and 4 coccygeal vertebrae. The vertebrae are movably secured together and in the normal spine form a double-S, reverse curve.
Chair backs generally have a substantially flat vertical surface which does not conform to the natural curvature of the back of a person sitting in the chair.
Improper support of the back of a person when sitting in a chair is a common cause of backache and pain in the lower back. Persons who sit at a desk or drive a vehicle for extended periods of time are often effected by this problem.
Typical automobile seats do not support the body properly and the lower back is usually in an awkward position with no support which results in poor sitting posture. Poor sitting posture causes muscle tension in the lower back if a person sits for an unusally long period of time, creating backaches and in some cases more serious spinal problems.
Heretofore, no device has been devised which is adjustable to the contour of the back of an individual while providing a firm support to relieve the spine of pressures exerted when a person is in the sitting position.